Steering column for motor vehicle

ABSTRACT

A steering column is structured such that a clamp/unclamp mechanism of a telescopic mechanism and a tilting mechanism can be operated by a single control lever located in the vicinity of a steering wheel, and that no part juts out of the steering column to improve reliability and controllability. When the control lever is pulled to rock on the center of the lever center axis, a tilt head is unclamped, while the rocking motion of the control lever turns a pusher plate, thereby pushing a pusher rod and also turning a column clamp shaft through a rocking arm. With the rotation of the column clamp shaft, the clamp is released to allow a column head to move. Since the column clamp shaft turns parallelly with the direction of movement of the column head, the column head can be clamped/unclamped regardless of its position.

This application is based on and claims the benefit of Applications Nos.2002-146694, No. 2002-245636, and No. 2002-273484 filed in Japan, thecontents of which are hereby incorporated by reference. In addition,this application is a continuation-in-part of and claims the benefit ofU.S. patent application Ser. No. 10/440,813, filed May 19, 2003, nowU.S. Pat. No. 6,902,192, issued Jun. 7, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a steering column, and more particularly, to asteering column for a motor vehicle having a telescopic mechanism and atilting mechanism.

2. Description of Related Art

The telescopic mechanism and the tilting mechanism of the steeringcolumn aim at adjusting the back-and-forth position and tilt angle of asteering wheel to the easiest-to-manipulate position according to thedriver's body form and taste.

The telescopic mechanism and the tilting mechanism have a clamp/unclampmechanism for adjusting the level and tilt angle of the steering wheel.When the adjustment is made, the clamp/unclamp mechanism is cancelledonce, and is operated to clamp again after the adjustment.

The adjustment of forward-and-backward position and tilt angle of thesteering wheel is performed by manipulating the steering wheel.Therefore, it is desirable to operate the clamp/unclamp mechanismwithout releasing the thumb from the steering wheel. There has beendisclosed in British Patent No. 2281375 a steering column fitted with asingle control lever which can be manipulated without removing the thumbfrom the steering wheel.

In the steering column disclosed in British Patent stated above, themovement of the control lever is transmitted to the back-and-forthposition adjusting clamp apparatus through a cable movable in a flexibletube. The cable and the tube have a large-radius curve of a sufficientlylittle curvature so that the cable can freely move in the entire rangeof adjustment of the steering wheel. The cable, therefore, partly jutsout of the outline of the steering column, not only looking awkward butbecoming a cause of trouble. Moreover, the transmission mechanismincluding the cable and the tube not only has low reliability but cannot smoothly operate because the cable is expandable.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide a steering columnequipped with a highly reliable, easy-to-operate clamp/unclampmechanism. The clamp/unclamp mechanism of either of the telescopicmechanism and the tilting mechanism has no part jutting out of thesteering column and is operated by a single lever located near thesteering wheel.

The telescopic mechanism, including the steering column, is clamped withthe frictional force. Since clamping is done by utilizing the frictionalforce, the clamp section is likely to slip when a great force isapplied. Passenger cars in these years have come to be equipped with anair bag system as standard equipment. The air bag system is designed onthe premise that the steering wheel is supported with stability when theair bag is operated. Therefore, it has been demanded that the steeringwheel will not move at the time of the secondary collision, that is, theclamp section of the telescopic mechanism will not slip with a forceresulting from the secondary collision.

In order to meet the demand stated above, therefore, it is anotherobject of this invention to provide the steering column that the clampsection will not easily slip with the force caused by the secondarycollision.

The objects stated above can be accomplished by the following means.That is, the steering column of the first invention is a steering columnwhich comprises: a fixed column member provided with a mounting sectionfor mounting said steering column to a vehicle body; a moving columnmember which is supported on said fixed column member and is unrotatablearound the center axis and movable in said direction of said centeraxis; a tilt head supported in a tiltable manner on one end side of saidmoving column member; a wheel shaft rotatably supported on said tilthead for fixing a steering wheel on one end; a control lever having arocking pivot shaft on said tilt head; a pusher rod slidably supportedon said member; a column clamp for clamping/unclamping said movingcolumn member on said fixed column member in relation to motion of saidpusher rod; a pusher plate for transmitting motion of said control leverto said pusher rod; and a tilt head clamp for clamping/unclamping saidtilt head on said moving column member in relation to motion of saidcontrol lever.

The steering column of the second invention is characterized in thepusher plate has a sufficiently wide contact surface capable of constantkeeping contact with said pusher rod within the entire tilt range ofsaid tilt head.

The steering column of the third invention is characterized in that, inthe steering column of the first invention, the pusher rod is providedwith a spring for pushing said pusher rod toward said pusher plate.

The steering column of the fourth invention is characterized in that, inthe steering column of the third invention, the spring functions toimpart a force to keep said control lever in a position off saidsteering wheel, and also said column clamp and said tilt head clamp inclamped positions thereof.

The steering column of the fifth invention is characterized in that, inthe steering column of the first invention, there exists a gap betweensaid pusher plate and said pusher rod in clamping state of said columnclamp.

The steering column of the sixth invention is characterized in that, inaddition to the steering column of the first invention, further includedis a column clamp shaft mounted on said moving column member androtatable around a center axis parallel with said center axis of saidmoving column member; and a rocking arm with one end engaged with saidpusher rod and with the other end fixed on said column clamp shaft;wherein with the operation of said control lever, a rocking motion ofsaid control lever is changed successively into a rocking motion of saidpusher plate, and an axial motion of said column clamp shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention andtogether with the description, serve to explain the principles of theinvention.

FIG. 1 is an outside view of a steering column 1;

FIG. 2 is an enlarged, partly cutaway view of a major portion of FIG. 1showing the steering column 1, and this view is commonly applicable tothe first to fifth embodiments;

FIG. 3 is a top partly cutaway view (as viewed in the direction P) ofFIG. 2, showing the steering column 1 of the First Embodiment;

FIG. 4 is a bottom view (as viewed in the direction Q) of FIG. 2,showing the steering column 1 of the first embodiment;

FIG. 5 is a cross sectional view of the steering column 1 of the firstto fifth embodiments, showing an A-A cross section in FIG. 2;

FIG. 6 is a cross sectional view of the steering column 1 of the firstto fifth embodiments, showing a B-B cross section in FIG. 2;

FIG. 7 is a cross sectional view of the steering column 1 of the firstto fourth embodiments, showing a C-C cross section in FIG. 2;

FIG. 8 is a partly enlarged view in FIG. 7, showing the position ofrotation of a column clamp shaft 6 in the unclamped position;

FIG. 9 is a partly enlarged view in FIG. 7, showing the position ofrotation of the column clamp shaft 6 in the clamped position;

FIG. 10 is a cross sectional view of the steering column 1 of the firstto fifth embodiments, showing a D-D cross section in FIG. 2;

FIG. 11 is an explanatory view showing, by a dot line and a solid line,two tilt positions of a tilt head 4 of the first embodiment;

FIG. 12 is a top partly cutaway view (as viewed in the direction P) ofFIG. 2, showing the steering column 1 of the second embodiment;

FIG. 13 is a top partly cutaway view (as viewed in the direction P) ofFIG. 2, showing the steering column 1 of the third embodiment;

FIG. 14 is a top partly cutaway view (as viewed in the direction P) ofFIG. 2, showing the steering column 1 of the fourth embodiment;

FIG. 15 is a partly enlarged view of the steering column of the fifthembodiment, corresponding to FIG. 8 of the first embodiment;

FIG. 16 is a partly enlarged view of the steering column 1 of the fifthembodiment; and

FIG. 17 is a partly enlarged view of the steering column 1 of the fifthembodiment partly modified.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, preferred embodiments of the present invention will be described indetail while referring to the accompanying drawings.

First Embodiment

*General Outline

FIG. 1 is an outside view of a steering column 1 according to the firstembodiment of this invention. The steering column 1 has a fixed columnmember 2, a moving column member 3, a column head 31, a tilt head 4, awheel shaft 5, a column clamp 21, a tilt head clamp 41 (see FIG. 2), acontrol lever 7, and a mechanical transmission apparatus.

The fixed column member 2 is fitted with mounting sections 221 and 222for mounting to the vehicle body 91. On the fixed column member 2 themoving column member 3 is supported unrotatably around the center axisand movably in the direction of the center axis. The column head 31 ismounted on one end of the moving column member 3. On the column head 31,the tilt head 4 is supported in such a manner that it can tilt on thecenter of a tilt center axis 43. On the tilt head 4 the wheel shaft 5 isrotatably supported. A steering wheel 92 is fixed on one end of thewheel shaft 5.

On the column head 31, a column clamp shaft 6, which is rotatable aroundan axis parallel with the center axis of the moving column member 3, ismounted. The fixed column member 2 has the column clamp 21. The columnclamp shaft 6 is movable in relation to the column clamp 21. With therotation of the column clamp shaft 6 the moving column member 3 can beclamped or unclamped.

The column head 31 is fitted with the tilt head clamp 41, which clampsand unclamps the tilt head 4 in relation to the column head 31. On thetilt heat 4 is supported the control lever 7 by means of the rockingpivot. The control lever 7 can be operated without removing the thumbfrom the steering wheel 92. The rocking motion of the control lever 7 ischanged into the rotation of the column clamp shaft 6 through themechanical transmission apparatus. The rotation is transmitted to thecolumn clamp 21 to thereby clamp/unclamp the moving column member 3.Furthermore, the rocking motion of the control lever 7 is transmitted tothe tilt head clamp 41, thus clamping/unclamping the tilt head 4.

The wheel shaft 5 is connected at one end to the universal joint 931 inthe steering column 1. The wheel shaft 5 is further connected to a frontwheel steering mechanism through a pair of upper intermediate shaft 941and lower intermediate shaft 942 which are splined (FIG. 3) and thelower universal joint 932. In FIG. 1, the dot line indicates someexamples of adjustments of the position and posture of the steeringwheel 92.

*Tilt Head Clamp

FIG. 2 is an enlarged, partly cutaway view of a major portion shown inFIG. 1, of the steering column 1. FIG. 3 is a top partly cutaway view ofthe steering column 1 as viewed from above (in the direction P). FIG. 4is a bottom view of the steering column 1 as viewed from below (in thedirection Q) in FIG. 2. FIGS. 5, 6, and 7 are sectional views takenalong lines A-A, B-B, and C-C in FIG. 2.

The tilt head clamp 41 is structured as described below. A segment gear33 (FIG. 2) having its center on the tilt center axis 43 is fastened tothe moving column member 3 by a bolt 34. And a back contact member 341is installed with a space provided between the contact member 341 andthe segment gear 33. Within the space stated above, a gear portion 442of the gear arm 44 rotatably supported on the center of a shaft 441 inthe tilt head 4 and a projecting portion 71 of the control lever 7 areinstalled.

The gear arm 44 is L-shaped, comprising a couple of legs. One of thelegs carries the gear portion 442. A spring 711 is interposed betweenthe other leg 443 of the gear arm 44 and the back of the projectingportion 71, to thereby provide a bias to widen a clearance between theback of the projecting portion 71 and the leg 443.

The projecting portion 71 is pressed leftward by the bias, therebypushing the gear portion 442 from behind. Therefore, the gear portion442 is pressed against the segment gear 33, so that the teeth of bothgears may be mutually engaged. When the gear portion 442 is pressedagainst the segment gear 33, the reaction to the projecting portion 71is received by the back contact member 341 (FIGS. 2 and 6), to therebylock the tilt head 4. The tilt head 4 is locked in stepped positions atan angle at which the gear portion 442 and the segment gear 33 can beengaged.

When the projecting portion 71 of the control lever 7 moves rightward inFIG. 2, the gear arm 44 is turned counterclockwise in FIG. 2 by theforce of the spring 711, disengaging these teeth. Therefore, when thetilt position is adjusted (at this time, the longitudinal position isalso adjustable), the projecting portion 71 is moved rightward by theoperation of the control lever 7.

*Universal Joint and Intermediate Shaft

As shown in FIG. 3, an upper universal joint 931 is located between theend of the upper intermediate shaft 941 and the end of the wheel shaft5. The center of the universal joint 931, being on the axis of the tiltcenter axis 43, will not be affected when the tilt head 4 is tilted.

The lower intermediate shaft 942 is rotatably supported on the fixedcolumn member 2. Since the lower intermediate shaft 942 and the hollowupper intermediate shaft 941 are splined, the moving column member 3 canmove rightward and leftward in FIG. 3. Because of the adoption ofsplines, the rotation of the upper intermediate shaft 941 can betransmitted to the lower intermediate shaft 942 regardless of theposition of movement. Accordingly, the rotation of the steering wheel 92can be transmitted to the lower intermediate shaft 942 if the level ofthe steering wheel 92 is adjusted.

*Fixed Column Member and Moving Column Member

As shown in FIG. 2, in the cylindrical portion of the moving columnmember 3, a long hole 32 is formed along the axial direction. In thelong hole 32, a stopper member 22 is engaged with the fixed columnmember 2 in the long hole 32. It is prevented by the long hole 32 andthe stopper member 22 that the moving column member 3 will come out ofthe fixed column member 2 and rotate in relation to the fixed columnmember 2. Therefore, the moving column member 3 is movable in the axialdirection in the fixed column member 2 and within the range of the longhole 32.

The fixed column member 2 has a cylindrical portion 231. Ring-shapedsliding guides 232 are provided in two positions in the cylindricalportion 231 (FIG. 3). The outside surface of the cylindrical portion ofthe moving column member 3, being guided by the sliding guide section232, is movable without a play in the axial direction of the movingcolumn member 3. A cushioning stopper 311 installed on the end face ofthe column head 31 is a cushioning material made of rubber, syntheticresin, or other adopted to prevent an impactive collision between metalparts in case of a collision of the moving column member 3 against theend face of the fixed column member 2 at the time of adjustment.

*Column Clamp

The structure of the column clamp 21 will be explained with reference toFIGS. 7, 8 and 9. FIG. 7 is a sectional view taken along line C-C inFIG. 2 as previously stated. And FIGS. 8 and 9 are partially enlargedviews in FIG. 7, showing a relationship between the rotational positionof the column clamp shaft 6 and the clamp/unclamp position. The columnclamp 21 is installed on the fixed column member 2, and has a firstwedge 211, a second wedge 212, a clamp bar 213, and reaction members2141 and 2142. The fixed column member 2 has a wedge hole 215 madelaterally. The wedge hole 215 is partly open to a cavity in the fixedcolumn member 2. The first wedge 211 and the second wedge 212 areprovided with inclined surfaces 2111 and 2112 respectively, and arelocated within the wedge hole 215 in such a manner that the inclinedsurfaces 2111 and 2112 will face each other. The inclined surfaces 2111and 2112 of these two wedges, therefore, face the outside surface of thecylindrical portion of the moving column member 3.

The first wedge 211 and the second wedge 212 have clamp bar holes 2113and 2114 through which the clamp bar 213 is inserted. On both ends ofthe clamp bar 213 the reaction members 2141 and 2142 which are larger inoutside diameter than the clamp bar holes 2113 and 2114 are secured. Theclamp bar 213 has a column clamp shaft hole 216 so formed as to contactone of the reaction members 2142. Through in this hole, a noncircularsectional portion of the column clamp shaft 6 which is substantiallyelliptical in shape is inserted.

On one end of the column clamp shaft 6 a rocking arm 61 is secured. Thedirection of the elliptical long diameter of the noncircular sectionalportion on the column clamp shaft 6 inclines at the time of unclampingas shown in FIG. 8, and the long-diameter portion faces the axialdirection of the clamp bar 213 at the time of clamping as shown in FIG.9. Because of this structure, when the rocking arm 61 is turned to rockfrom the position in FIG. 8 the column clamp shaft 6 turns to theposition in FIG. 9. At this time, when the reaction member 2142 ispressed leftward by one of the elliptical long-diameter portions, theclamp bar 213 is pulled leftward. Furthermore, the reaction member 2141presses the first wedge leftward. On the other hand, the second wedge ispushed rightward by the other of the elliptical long-diameter portion.

As a result of the mutual approach of the two wedges, the inclinedsurfaces 2111 and 2112 press the outside surface of the cylindricalportion of the moving column member 3, to thereby clamp the movingcolumn member 3 to the fixed column member 2. The first wedge 211 andthe second wedge 212 can slightly move rightward and leftward as onebody, and therefore there will never occur such an unbalanced movementthat only one wedge will firmly press the moving column member 3.

When the rocking arm 61 is turned to rock in an opposite direction, thefirst wedge 211 and the second wedge 212 move reversely to go apart fromeach other, thus unclamping the moving column member 3.

*Control Lever and Related Operation

Next, each member operating in interlock with the operation of thecontrol lever 7 will be explained. The control lever 7 is located belowthe steering column 1. In FIG. 3, the control lever 7, a lever centeraxis 72 which is the center of rocking motion, a pusher plate 73 fixedon the control lever 7, and a pusher rod 74 are partly visible. In FIG.4 giving a bottom view of these parts, the state of the whole body ofthe control lever 7 and the control lever operated to adjust the leveland tilt of the steering wheel (i.e., the control lever end 701 of thecontrol lever 7 pulled up toward the steering wheel 92) is indicated bythe solid line (the dot line indicates the control lever unoperated).

The pusher rod 74 having a collar 742 is slidably supported on thecolumn head 31 so as to be slidable in a direction parallel with thetilt center axis 43. Through on the pusher rod 74, a spring 741 ismounted to push the collar 742 leftward in FIG. 10. In the end portionof the pusher rod 74 there is formed a small long hole 743 in thedirection at right angles to the pusher rod 74 the end of the pusher rod74 is axially engaged with one end of the rocking arm 61 through thelong hole 743. The long hole 743 functions to absorb the amount ofdeparture from the rocking arm 61 when the pusher rod 74 is axiallymoved.

As the pusher rod 74 is moved leftward by the spring 741, the rockingarm 61 axially engaged with the right end of the pusher rod 74 isapplied with a turning force to turn clockwise. The rocking forceexerted to the rocking arm 61 holds the column clamp shaft 6 in theclamp position (FIG. 9. Note that the position in FIG. 9 differs indirection in FIG. 10). The rocking arm 61 in this position is indicatedby a solid line. It does not matter whether a gap exists or not betweenthe left end of the pusher rod 74 and the pusher plate 73 when themoving column member 3 is clamped to the fixed column member 2. In theformer case, the pusher plate 73 strikes against the pusher rod 74 aftersome idle motion during the gap when the control lever 7 is operated forunclamping.

*Pusher Plate

The tilt head 4 tilts on the column head 31. Therefore in accordancewith the amount of tilt (angle), the position of the pusher rod 74 inrelation to the pusher plate 73 varies. In FIG. 11, two tilt positionsof the tilt head 4 are indicated by a dot line and a solid line. Thepusher rod 74, being supported on the column head, will not be changedin position by tilting. The pusher plate 73, located off the tilt centeraxis 43, will change in position in relation to the pusher rod 74 whentilted. Therefore, the pusher plate 73 is provided with a wide contactsurface bent like a hockey stick head so that the pusher rod 74 maycontact the pusher plate 73 at any angle.

*Steering Wheel Adjustment

Adjustments of level and tilt angle of the steering wheel 92 andoperation of each member will hereinafter be explained. The driver pullsup the control lever 7 by extending for example all the fingers exceptthe thumb which is left unreleased from the steering wheel 92 (FIG. 3).Thus, the control lever 7 turns on the center of the lever center axis72 as shown in FIG. 4 (FIG. 4 is a bottom view, in which, therefore, theright and left sides are reversed).

With the operation of the control lever 7 the projecting portion 71moves to the right in FIG. 2 to turn the gear arm 44 counterclockwise.As the gear arm 44 turns, the gear portion of the gear arm 44 isdisengaged from the teeth of the segment gear 33, so that the tilt head4 becomes tiltable (as indicated by a solid line in FIG. 4).

At the same time, the rocking motion of the control lever 7 rocks thepusher plate 73 (FIG. 4). By the rocking motion, the pusher plate 73overcomes the force of the spring 741, pushing the pusher rod 74 upwardin FIG. 4. In FIG. 10 the movement stated above corresponds to therightward movement of the pusher rod 74.

The rightward movement of the pusher rod 74 rocks the rocking arm 61 andaccordingly turns the column clamp shaft 6 (FIG. 10). As the columnclamp shaft 6 turns, the long-diameter portion thereof in the horizontalposition as shown in FIG. 9 inclines as shown in FIG. 8. Thus, the firstwedge 211 and the second wedge 212 that have approached each other asshown in FIG. 7 move away from each other to unclamp the moving columnmember 3.

The tilt head 4 is tiltable and the column head 31 is longitudinallymovable. Therefore, the driver can adjust the back-and-forth positionand the tilt position (angle) of the steering wheel 92 without removingthe thumb from the steering wheel 92 and the control lever 7. When thetilt head clamp 41 is released, the weight of the tilt head 4 acts as adownward force on the tilt head 4, which therefore tilts down just likea man's drooping of his head. To counterbalance the downward force,therefore, there is provided a strong spring 45 (FIG. 4). The tilt head4 is applied with a force for holding the steering wheel 92 in the topinclined position, so that the driver can easily get on and off themotor vehicle.

When the finger is removed from the control lever 7 after adjustment,the control lever 7 goes back to the original position (the positionindicated by a solid line in FIG. 3) by the force of the spring 741 (andthe spring 711). As the control lever 7 returns to the originalposition, the tilt head 4 and the column head 31 (the moving columnmember 3) are both clamped by reversing the above-described operation.The spring 741 functions to apply a force to hold the control lever 7off the steering wheel 92 and to hold the column clamp 21 and the tilthead clamp 41 in their clamped positions respectively when the controllever 7 is not operated.

The operating portion (the top portion) of the control lever 7, ifexcessively pulled up close to the steering wheel 82, will interferewith the manipulation of the steering wheel during driving. Therefore,when no adjustment is made of the back-and-forth position and angle ofthe steering wheel, the operating portion stated above moves to aposition an appropriate distance from the steering wheel. Furthermore,to reliably prevent such an interference, the control lever 7 may bestructured to be foldable or extendable. Examples (second, third andfourth embodiments) of the collapsible control lever 7 will be givenbelow.

Second Embodiment

The steering column 1 of the second embodiment, except the structure ofthe control lever 7, has a structure common to that of the steeringcolumn of the first embodiment. To avoid redundancy of explanation, onlythe control lever 7 and related structures which are different from thefirst embodiment will be explained, using the same reference numerals asthose used in the explanation of the first embodiment.

FIG. 12 is a top view, partly cut away, of the steering column 1according to the second embodiment. FIG. 12 corresponds to FIG. 3 in thefirst embodiment. The control lever 7 in the second embodiment has acontrol lever body 705 and a control lever end 701 pivotally supportedthereon. The control lever end 701 is foldable in between the operatingposition and the retreat position. In the operating position, thecontrol lever 7 is operable by other fingers with the thumb left on thesteering wheel 92. In the retreat position, the control lever is apartfrom the steering wheel 92 and can not be operated with the thumb lefton the steering wheel 92.

The control lever end 701 is pivotally supported by a pivot shaft 702 onthe end portion of the control lever body 705. On the pivot shaft 702 aspring (e.g., a coil spring 703) is fitted. Two hooked ends of the coilspring 703 are set respectively on the control lever body 705 and thecontrol lever end 701. By the coil spring 703 the control lever end 701is applied with a bias force for folding the control lever in theretreat position indicated by a solid line in FIG. 12.

When adjusting the back-and-forth position and tilt angle of thesteering wheel 92, the driver pulls out the control lever end 701 byreleasing the finger once from the steering wheel 92. Thereafter, withthe thumb put on the steering wheel 92, the driver pulls the controllever 7 by other finger. The control lever 7 thus pulled turns on thecenter of the lever center axis 72 as indicated by the dot line in FIG.12. Therefore, both the tilt head 4 and the column head 31 (the movingcolumn member 3) are unclamped by the same operation as the operationexplained in the first embodiment. In this state, the back-and-forthposition and tilt angle of the steering wheel 92 are adjusted.

Then, when the finger is removed from the control lever 7 the tile head4 and the column head 31 (the moving column member 3) are clamped by thesame operation as that explained in the first embodiment. At the sametime, the control lever end 701 is folded by the bias force of the coilspring 703. The control lever end 701, moving back to the retreatposition, will not interfere with the manipulation of the steering wheel92 during driving.

Third Embodiment

The steering column 1 of the third embodiment has a structuresubstantially common to the steering column of the first embodimentexcepting the provision of the cowl 35 and the structure of the controllever 7. To avoid redundancy of explanation, only the cowl 35, thecontrol lever 7 and related structures which are different from thefirst embodiment will be explained; the same reference numerals as thoseused in the explanation of the first embodiment will be used.

FIG. 13 is a top view, partly cut away, of the steering column 1according to the third embodiment. FIG. 13 corresponds to FIG. 3 in thefirst embodiment. The cowl 35 is a cover for covering the tilt head 4and the moving column member 3, and is fixed on the tilt head 4. Thecowl 35 has a shaft hole 3 through which the wheel shaft 5 is mounted,and a lever hole 352 through which the control lever 7 is mounted.

In the side of the cowl 35, a dent is formed so that a part of thecontrol lever end 701 folded can fit therein. In the vicinity of thisdent there is formed a locking hole 354, in which the locking projection704 provided on the control lever end 701 can fit.

Similarly to the steering column of the second embodiment, the controllever end 701 is pivotally supported by the pivot shaft 702. On thepivot shaft 702 a spring (e.g., a coil spring 703) is fitted. The twohooked ends of the coil spring 703 are set on the control lever body 705and the control lever end 701 respectively. The control lever end 701 isapplied with a bias force by the coil spring 703, to thereby fold thecontrol lever 7 into the retreat position indicated by a solid line inFIG. 13.

Since the locking projection 704 fits in the locking hole 354, therewill not occur such an accident that the control lever 7 malfunctions(unclamps) if thrust rightwardly in the event of a collapse by thesecondary collision of the motor vehicle. The air bag installed in thesteering wheel 92 is able to keep a normal position, thus enablingnormally operating in the event of the secondary collision. The lockinghole 354 may be formed directly in the tilt head 4.

In the third embodiment described above, the locking hole 354 is presentin the cowl 35, but may be formed directly in the body of the tilt head4. In the case of the steering column having no cowl 35, it is possibleto eliminate the problem of unclamping in the event of the secondarycollision.

Fourth Embodiment

The steering column of the fourth embodiment has substantially the samestructure as the first, second and third embodiments. No explanationwill be given of overlaps of the embodiment. Furthermore, referencenumerals used are substantially similar to those used in the explanationof the embodiments. The control lever 7 in the steering column is foldedso that the control lever end 701 thereof will retreat to a position faraway from the steering wheel 92. It should be noted, however, that thecontrol lever is not fully folded like in the second and thirdembodiments. FIG. 14 is a top view, partly cut away, of the steeringcolumn according to the fourth embodiment corresponding to FIG. 3 in thefirst embodiment, and to FIG. 13 in the third embodiment.

The pivot shaft 702 and the coil spring 703 for folding the controllever end 701 are located near the root of the control lever 7. Thecontrol lever body 705 is provided with the locking surface 706 in orderthat, when retreating (during driving), the control lever end 701 willstop in a direction at about right angles to the control lever body 705.At the time of retreat, the control lever end 701 biased by the coilspring 703 hits on the locking surface, stopping in this position.

Fifth Embodiment

As previously explained, the clamp section of the telescoping mechanismis demanded not to slip with a force caused by the secondary collisionwhen the air bag is operated. The steering column of the presentembodiment can receive part of a force of a collision not only at thecolumn clamp but at the column clamp shaft 6, whereby the air bag can beproperly operated. The steering column of the fifth embodiment hassubstantially the same structure as those of the first to fourthembodiments on the whole. The overlapped part, therefore, will not beexplained. Reference numerals are substantially the same as those usedin the explanation of these embodiments.

FIG. 15 is a cross sectional view taken along line C-C which correspondsto FIG. 8 of the first embodiment; and FIG. 16 is an enlarged view ofthe column clamp shaft 6 and the second wedge 212. The end face of thesecond wedge 212 facing the column shaft 6, and the long-diameterportion of the column clamp shaft 6, that is, the portion facing thesecond wedge 212, are provided with projections and depressions 2121 and601 respectively. These projections and depressions are mutuallyengageably formed. Therefore when the moving column member 3 is in aclamped state, the projections and depressions are engaged, so that apart of the force exerted to the wheel shaft 5 upon the secondarycollision will be received by the column clamp shaft 6. Furthermore, asshown in FIG. 17, the projections and depressions 2143 and 602 may beformed on the other side of the column clamp shaft 6 and on the reactionmember 2143.

According to the steering column of this invention, the telescopicmechanism and the tilting mechanism are clamped/unclamped by means of asingle lever mounted in the vicinity of the steering wheel. Therefore,there exists no part appearing outside of the steering column, thusenabling reliable, smooth operation of the steering column. According tothe steering column having the foldable control lever, eachclamp/unclamp mechanism is hard to unclamp upon the secondary collision.The air back, therefore, can be reliably operated upon the secondarycollision.

Although only preferred embodiments are specifically illustrated anddescribed herein, it will be appreciated that many modifications andvariations of the present invention are possible in light of the aboveteachings and within the purview of the appended claims withoutdeparting from the spirit and intended scope of the invention.

1. A steering column for a motor vehicle comprising: a fixed columnmember provided with a mounting section for mounting said steeringcolumn to a vehicle body; a moving column member which is supported onsaid fixed column member and is unrotatable around a center axis andmovable in the direction of said center axis; a tilt head supported in atiltable manner on one end side of said moving column member; a wheelshaft rotatably supported on said tilt head for fixing a steering wheelon one end; a control lever having a rocking pivot shaft on said tilthead; a pusher rod slidably supported on said moving column member; acolumn clamp for clamping/unclamping said moving column member on saidfixed column member in relation to motion of said pusher rod; a pusherplate for transmitting motion of said control lever to said pusher rod;and a tilt head clamp for clamping/unclamping said tilt head on saidmoving column member in relation to motion of said control lever.
 2. Asteering column according to claim 1, wherein said pusher plate has asufficiently wide contact surface capable of constant keeping contactwith said pusher rod within the entire tilt range of said tilt head. 3.A steering column according to claim 1, wherein said pusher rod isprovided with a spring for pushing said pusher rod toward said pusherplate.
 4. A steering column according to claim 3, wherein said springfunctions to impart a force to keep said control lever in a position offsaid steering wheel, and also said column clamp and said tilt head clampin clamped positions thereof.
 5. A steering column according to claim 1,wherein there exists a gap between said pusher plate and said pusher rodin clamping state of said column clamp.
 6. A steering column accordingto claim 1, further comprising: a column clamp shaft mounted on saidmoving column member and rotatable around a center axis parallel withsaid center axis of said moving column member; and a rocking arm withone end engaged with said pusher rod and with the other end fixed onsaid column clamp shaft; wherein with the operation of said controllever, a rocking motion of said control lever is changed successivelyinto a rocking motion of said pusher plate and an axial motion of saidcolumn clamp shaft.